Safety latch mechanisms

ABSTRACT

An economical child-proof rotatably actuated latch mechanism comprised of a casing-less assembly which includes a manually rotatable shaft extending through a closure member and supporting a cammed rollback at the inner end thereof. The rollback engages a notch in a reciprocally slidable spring-biased latch bar. The latch bar is slidably carried by a support member directly attached to the inner surface of the closure member. An adjustable spring is biased between the latch bar and the support member to continuously urge the latch bar into engagement with a keeper plate mounted on an adjoining closure member.

United States Patent Lambrecht [451 Jan. 14, 1975 SAFETY LATCH MECHANISMS [76] Inventor: Robert E. Lambrecht, 409 Snow Ave., Sugar Grove, 111. 60554 22 Filed: May3, 1973 211 App1.No.:357,006

[52] US. Cl 292/169, 292/337, 292/DIG. 60 [51] Int. Cl. E051: l/l2 [58] Field of Search 70/DIG. 53; 292/169, 169.14, 292/169.15,169.16,169.17,l69.18, DIG.

51, DIG. 60, DIG. 61

[56] References Cited UNITED STATES PATENTS 695,263 3/1902 Abrams 292/169.14

1,072,593 9/1913 Erz 292/169.l5 1,187,756 6/1916 McQuillen 292/8 2,110,920 3/1938 Schnitzler 292/79 2,755,120 7/1956 Young et a1. 292/74 FOREIGN PATENTS OR APPLICATIONS 81,750 l/1957 Denmark 292/DIG. 51

Primary ExaminerAlbert G. Craig, Jr. Attorney, Agent, or Firm-Hill, Gross, Simpson, Van Santen, Chiara & Simpson [57] ABSTRACT An economical child-proof rotatably actuated latch mechanism comprised of a casing-less assembly which includes a manually rotatable shaft extending through a closure member and supporting a cammed rollback at the inner end thereof. The rollback engages a notch in a reciprocally slidable spring-biased latch bar. The latch bar is slidably carried by a support member directly attached to the inner surface of the closure member. An adjustable spring is biased between the latch bar and the support member to continuously urge the latch bar into engagement with a keeper plate mounted on an adjoining closure member.

3 Claims, 9 Drawing Figures SAFETY LATCH MECHANISMS BACKGROUND OF THE DISCLOSURE 1. Field of the Invention The invention relates to child-proof latch mechanisms and somewhat more particularly to an economical casing-less latch mechanism which may be fabricated on-site and installed by an ordinary person.

2. Prior Art It has long been recognized that young children must be protected from access to various harmful drugs, pills, liquids, powders, cleansers, etc., commonly found in homes. Child-proof locks and latches are available as pre-assembled and/or expensively encased mecha nisms. Exemplary prior art mechanisms of this type are illustrated in US. Pat. Nos. 3,206,238; 1,871,633 and 1,752,559. Such pre-assembled safety mechanisms require the services of a highly skilled and highly priced cabinet artisan, along with his specialized tools. Accordingly, persons of ordinary skill or of modest economical means have not been able to satisfactorily protect their young children.

SUMMARY OF THE INVENTION The invention provides an economical easily fabricatable and installable safety latch mechanism for various household closure means.

It is a novel feature of the invention to provide a casingless safety latch assembly comprised of elements which are readily adjustable at a given site and are easily installed by an ordinary person, with ordinary household tools.

It is a further novel feature of the invention to provide a casing-less safety latch assembly comprised of a rotatable shaft extending through a closure member and carrying a cammed rollback at an inner end thereof. A notched latch bar is mounted for reciprocal movement on a support member attached to the inner or back side of a closure member and positioned so that the rollback engages the notch of the latch bar. An ad justable spring is mounted between the latch bar and the support member to bias the latch bar against a keeper mounted on an adjoining closure member.

Other and further features of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show preferred embodiments of the present invention and the principles thereof and what is now considered to be the best mode contemplated for applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the spirit and scope of the appendant claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial side elevational view, with some parts omitted and some parts in phantom, illustrating a hinged door which includes a latch mechanism constructed in accordance with the principles of the invention;

FIG. 2 is a sectional view taken along lines 2-2 of FIG. 1;

FIg. 3 is a vertical sectional view taken along lines 3--3 of FIG. 2;

FIG. 4 is a side elevational view ofa portion of a latch bar support member forming a part of the invention;

FIG. 5 is a partial top view of a latch bar and associ ated elements assembled in accordance with the principles of the invention;

FIG. 6 is a vertical sectional view taken along lines 6-6 of FIG. 5;

Flg. 7 is a top plan view of a partially broken-away latch bar of the invention;

FIG. 8 illustrates a modified embodiment of a latch bar support member forming a part of the invention; and

FIG. 9 is a top plan view taken along lines 9-9 of the embodiment illustrated at FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention provides an economical child-proof casing-less latch assembly comprised of elements which are readily adjustable onsite to fit various closure means. The operation of the latch assembly is simply adjusted during or after assembly in accordance with the degree of difficulty desired for opening the latch mechanism. The safety latch mechanism of the invention is readily tailored to fit any closure means, such as cabinets, drawers, hinge doors, sliding doors, windows and other similar closure means which include two separate closure members. The thickness and configuration of the closure members may vary as desired without substantial effect on the mountability thereon of the latch mechanism of the invention. The latch mechanism of the invention is readily installed in combination with or in place of existing handles or the like on closure members.

Referring now to the drawings, wherein similar elements are designated with identical reference numerals, FIG. 1 illustrates a casing-less latch mechanism or assembly 10 of the invention mounted in operating relation on a closure means having a first closure member 21, such as a hinged door, and a second closure member 29, such as a door jamb.

The latch mechanism or assembly 10 includes a manually rotatable shaft means 20 having a grasping portion, such as knob 17 and an operating shaft portion 18 of a length sufficient to extend through the thickness of a first closure member 21. When mounted on a closure member, the knob 17 is positioned on one side of the closure member and the operating portion 18 extends to the opposite side thereof. A support member 31 is also included in assembly 10 for mounting in close proximity to the operating shaft portion 18. The support means has slots or the like for receiving and slidably supporting a latch bar 11. The latch bar 11 is of a length sufficient to extend between the operating shaft portion 18 and an adjacent edge of a second closure member 29 and thereby prevent movement between the closure members until the latch bar is withdrawn. A rollback means (best seen in FIGS. 2, 3 and 5) is interconnected between the operating shaft portion 18 and the latch bar 11 so that upon rotation of knob 17, the latch bar is reciprocally moved away from the adjacent edge of the second closure member and the closure means is opened.

The latch bar, as best seen in FIG. 7, may be of any length and preferably comprises standard commercial small bar stock of rectangular cross-section. A rectangular actuation slot 12 having walls l3, l4 and 15 may be provided at one side adjacent an end of bar 11 prior to retail of the assembly or may be cut on-site, as with a hack saw. The other end 16 of bar 11 is usually square, as manufactured, and may, if desired, be cut on-site at an angle to form a striking end 16, as when the biased cut location in relation to a stacking plate or keeper has been determined by on-site measurements. The angular cut will allow the closure member to be closed without coaction of means 20; slot wall 14 being far enough away as to not interfere with cammed rollback 24. Of course, a square striking end may also be utilized if desired.

The manually operable circular knob 17, best seen at FIG. 2, is attached to a shaft portion 18 of any desired length. The length of shaft 18 is readily adjusted, as by cutting with a hack saw on-site, in accordance with the thickness of a closure member. A cammed rollback 24 is provided for mounting on the free or inner end of the shaft 18, in any suitable manner as by a pressure fit or with a set screw. The rollback 24, as best seen at FIG. 3, includes a cammed surface 240, which in assembly engages the wall 13 of the actuator slot 12 in bar 11 and a flat surface 24b which engages wall 15 of slot 12. The coaction between the rollback 24 and the slot 12 limits the maximum projection of the striking end 16 of bar 11 toward the second closure member 29.

A retracting means, such as a coil spring 63, best seen in FIG. 3, may be provided connecting the rollback 24 to an immovable portion, such as leg 33 for restoring the rollback to its normal position.

A bearing collar 22, best seen at FIG. 2, is provided for mounting on shaft 18 intermediate the grasping portion and its free end for securing the knob 17 to the closure member 21, as by a set screw 23. v

A latch bar support member 31, best seen at FIGS. 4, and 6, may be stamped from flat steel as a somewhat U-shaped bracket having a base 32 and two upstanding legs 33 and 34 which are longitudinally spaced apart. The legs 33 and 34 are each provided with a support slot 35 and 36 respectively of a width and length sufficient to loosely receive a latch bar 11. The base 32 is provided with a plurality of slots 57 and 58, shown in FIG. 4 as being vertically disposed, although it will be appreciated that such slots may extend in both the vertical and horizontal directions. The slots 57 and 58 allow the support member 31 to be mounted along a closure surface at any select location. The legs 33 and 34 are also provided with anchoring slots 61 and 62 below the support slots 35 and 36 for anchoring guide plates 51 and 52 onto legs 33 and 34. The guide plates 51 and 52 are detachable and each include a curved lip 53 which hooks over the top edge of the legs 33 and 34. The guide plates may also be attached by eliminating the curved lip, and adding additional guide plate anchoring slots as 61 and 62, to the opposing side of legs 33 and 34. Each plate is provided with a horizontal slot 54 of a size to fairly snugly embrace the latch bar 11 while allowing it to reciprocally move during actuation. Each plate 51 and 52 is also provided with an opening 54a below slot 54 for securing the guide plates with their respective legs. The slot 54 and openings 54a of guide plates 51 and 52 are stamped or otherwise produced so as to be in alignment with the support slots 35 and 36 and anchoring slots 61 and 62 respectively for ease of assembly. The plates 51 and 52 are thus selectively positionable along legs 33 and 34 as required for proper operation. The anchoring means, such as bolt 59 and nut is provided for securing the plates at a select location on the legs. Suitable fastening means, such as wood screws or the like, are also provided for anchoring the support member 31 to the slots 57 and 58 on the inner or back side of a closure member.

As best seen in FIGS. 2 and 3, a coiled compression spring 25 is provided of a length sufficient to fit between the legs 33 and 34 of the support member 31. The spring 25 has a coil diameter of a size sufficient to encompass the latch bar 11. A retaining collar 26 is mounted on the latch bar, as by a set screw, to compress the spring 25 against leg 33 for biasing the bar toward a striker plate 28 which is mounted on an adjacent closure member 29. The position of retaining collar 26 may be adjusted as desired during or after assembly and by increasing the compression of the spring, an increase in the difficulty of actuating the latch assembly is achieved.

A modified embodiment of a latch support member 40 is shown in FIGS. 8 and 9. Member 40 is particularly useful for installation on very thin closure members, as may be found in some plywood, plastic or metal furniture. A flat sheet of steel is stamped or otherwise formed so as to include a reverse bent end portion 41 integral with a base portion 42 and a pair of upstanding legs 44 and 43. The leg 44, as best seen at FIG. 9, is struck out from the base at a angle, while leg 43 is bent upwardly from the sheet end opposite the one forming portion 41. The reverse bent end portion 41 is provided with aligned holes 45 and 46 to define spacedapart bearing surfaces for the operating shaft portion 18. Each of the legs 43 and 44 are provided with support slots 43a and 44a respectively, similar to slots 35 and 36 described in conjunction with support members 31. Similar latch bar support or guide plates, such as 51 and 52 earlier described, together with appropriate slots and anchoring means are utilized in combination with support members 40. Further, while separate mounting holes 40a are shown, vertical and/or horizontal slots may be utilized for mounting members 40 in an adjustable manner on a closure member.

As shown in FIG. 2, in some installations, it may be desirable to combine the latch assembly 10 of the invention with a pre-existing closure handle 47. Of course, a closure handle 47 may also be installed after the latch assembly 10 has been installed. It is preferable to locate the knob 17 within the embrace of a handle 47 so as to make it even more difficult for a small child to sufficiently rotate'the knob for releasing the latch, without seriously interferring with actuation thereof by an adult.

In assembling, a home handyman bores a hole 19 (FIG. 2) through a closure member, such as 21, in an approximately optimum position. Because of the easy adjustability of various elements in achieving operation, the handyman need not be very precise in locating his initial bore. The handyman then inserts the shaft means through the hole and shortens the free end thereof as desired. He then slips the bearing collar 22 thereon and secures it in place so that the shaft means is readily rotatable. The rollback 24 may then be attached to the free end of shaft 18. Next, the handyman mounts a support member, such as 31 or 40 on the inner side of the closure member in close proximity to the shaft 18 and adjust the support member as necessary in the space between the shaft 18 and the end of the closure member. The latch support plates are then mounted on the legs of a support member. The latch bar is then cut to proper length to extend at least between the shaft 18 and the adjacent edge of a second closure member. The latch bar is next inserted, together with the compression spring and retaining collar between the slots of the support plates. The plates are then adjusted to align the rollback with the actuation notch in the bar for proper operation and the spring compressed to a select degree. A keeper plate 28 may then be mounted on the adjacent edge of the other closure member and the assembly is ready for use.

The compression spring and retaining collar embracing the latch bar are readily accessible and may be adjusted from time to time as necessary so that the effort needed to retract the latch will exceed the finger strength of young growing children but allow older and stronger persons to operate the latch as desired.

The entire inner portion of the latch mechanism can be easily adjusted after installation. The latch bar support plates 51 and 52 are easily adjustable toward or away from the base of a support member by simply loosening and re-tightening the bolts and nuts holding the plate on the support legs. Likewise, the entire support member may be moved along a closure member as desired. This easy adjustability of the elements in the latch mechanism renders it possible to maintain the assembly in prime operating condition at all times.

The latch assembly of the invention allows the public to economically and simply provide protection for young children. The low cost of manufacture and installation of the latch mechanism makes it attractive to persons of very limited economic means, who seek to protect their young children in modest homes or even in slum-type environments where high cost protective or safety devices are unavailable.

It will be understood that the invention is not limited to the embodiments or details of construction herein disclosed and that its scope embraces such modifications, variations and alterations as are comprehended by the spirit of the invention and the appendant claims.

I claim as my invention:

1. A casingless safety latch assembly adaptable for mounting on a closure means which includes two separate closure members, said assembly comprising:

manually rotatably shaft means including a grasping portion and an operating portion of a given length for extending through a bore in a first closure member, with said grasping portion being on one side of said first closure member and said operating portion being on an opposite side thereof;

support means for mounting on said opposite side of the first closure member in close proximity to said operating shaft portion;

said support means comprising a U-shaped member having a pair of longitudinally spaced-apart legs and a base wall of substantial width integrally joining said legs to one another;

said base wall having a plurality of spaced slots therein extending crosswise of the width of the base wall and through which slots fasteners extend for mounting said support means onto the first closure member in adjustable relation lengthwise of the slots;

said legs each including a slot extending lengthwise of the leg for receiving and slidably supporting a latch bar and permitting adjustment of the latch bar along the leg slots;

a latch bar of a length sufficient to extend between said operating shaft portion and an edge of a second closure member, said latch bar being slidably mounted in the leg slots of said support means;

rollback means connected to said shaft portion and engaging an adjacent end portion of said latch bar for reciprocally moving said bar in said leg slots on rotation of said shaft means; and

spring means mounted between said support means and said latch bar for biasing said latch bar toward the edge of said second closure member.

2. A casingless safety latch assembly adaptable for mounting on a closure means which includes two separate closure members, said assembly comprising:

manually rotatably shaft means including a grasping portion and an operating portion of a given length for extending through a bore in a first closure member, with said grasping portion being on one side of said first closure member and said operating portion being on an opposite side thereof;

support means for mounting on said opposite side of the first closure member in close proximity to said operating shaft portion, and having spaced apart legs with aligned slots for receiving and slidably supporting a latch bar;

a latch bar of a length sufficient to extend between said operating shaft portion and an edge of a second closure member, said latch bar being slidably mounted in the slots of said support legs;

rollback means connected to said shaft portion and engaging an adjacent end portion of said latch bar for reciprocally moving said bar on rotation of said shaft means;

spring means mounted between said support means and said latch bar for biasing said latch bar toward the edge of said second closure member;

a pair of guide plates adjustably mounted on said spaced apart legs, each plate having a slot aligned with the respective leg slot for receiving and slidably supporting the latch bar; and

means for anchoring the plates at a selected position on the respective legs.

3. A casingless safety latch assembly adaptable for mounting on a closure means which includes two separate closure members, said assembly comprising:

manually rotatably shaft means including a grasping portion and an operating portion of a given length for extending through a bore in a first closure member, with said grasping portion being on one side of said first closure member and said operating portion being on an opposite side thereof;

support means for mounting on said opposite side of the first closure member in close proximity to said operating shaft portion;

a latch bar of a length sufficient to extend between said operating shaft portion and an edge of a second closure member;

rollback means connected to said shaft portion and engaging an adjacent end portion of said latch bar for reciprocally moving said bar on rotation of said shaft means;

said support means being an integral member which includes a reverse bent edge portion having aligned holes therethrough for receiving said operating shaft portion, a pair of longitudinally spaced apart legs having openings therein for receiving and slidably supporting the latch bar and a base wall interality of slots for receiving fasteners for mounting grally joining said reverse bent edge portion with spring means mounted between said support means Spaced apart legs sald base Wan havmg a and said latch bar for biasing said latch bar toward the edge of said second closure member.

said support means on the first closure member;

and 

1. A casingless safety latch assembly adaptable for mounting on a closure means which includes two separate closure members, said assembly comprising: manually rotatably shaft means including a grasping portion and an operating portion of a given length for extending through a bore in a first closure member, with said grasping portion being on one side of said first closure member and said operating portion being on an opposite side thereof; support means for mounting on said opposite side of the first closure member in close proximity to said operating shaft portion; said support means comprising a U-shaped member having a pair of longitudinally spaced-apart legs and a base wall of substantial width integrally joining said legs to one another; said base wall having a plurality of spaced slots therein extending crosswise of the width of the base wall and through which slots fasteners extend for mounting said support means onto the first closure member in adjustable relation lengthwise of the slots; said legs each including a slot extending lengthwise of the leg for receiving and slidably supporting a latch bar and permitting adjustment of the latch bar along the leg slots; a latch bar of a length sufficient to extend between said operating shaft portion and an edge of a second closure member, said latch bar being slidably mounted in the leg slots of said support means; rollback means connected to said shaft portion and engaging an adjacent end portion of said latch bar for reciprocally moving said bar in said leg slots on rotation of said shaft means; and spring means mounted between said support means and said latch bar for biasing said latch bar toward the edge of said second closure member.
 2. A casingless safety latch assembly adaptable for mounting on a closure means which includes two separate closure members, said assembly comprising: manually rotatably shaft means including a grasping portion and an operating portion of a given length for extending through a bore in a first closure member, with said grasping portion being on one side of said first closure member and said operating portion being on an opposite side thereof; support means for mounting on said opposite side of the first closure member in close proximity to said operating shaft portion, and having spaced apart legs with aligned slots for receiving and slidably supporting a latch bar; a latch bar of a length sufficient to extend between said operating shaft portion and an edge of a second closure member, said latch bar being slidably mounted in the slots of said support legs; rollback means connected to said shaft portion and engaging an adjacent end portion of said latch bar for reciprocally moving said bar on rotation of said shaft means; spring means mounted between said support means and said latch bar for biasing said latch bar toward the edge of said second closure member; a pair of guide plates adjustably mounted on said spaced apart legs, each plate having a slot aligned with the respective leg slot for receiving and slidably supporting the latch bar; and means for anchoring the plates aT a selected position on the respective legs.
 3. A casingless safety latch assembly adaptable for mounting on a closure means which includes two separate closure members, said assembly comprising: manually rotatably shaft means including a grasping portion and an operating portion of a given length for extending through a bore in a first closure member, with said grasping portion being on one side of said first closure member and said operating portion being on an opposite side thereof; support means for mounting on said opposite side of the first closure member in close proximity to said operating shaft portion; a latch bar of a length sufficient to extend between said operating shaft portion and an edge of a second closure member; rollback means connected to said shaft portion and engaging an adjacent end portion of said latch bar for reciprocally moving said bar on rotation of said shaft means; said support means being an integral member which includes a reverse bent edge portion having aligned holes therethrough for receiving said operating shaft portion, a pair of longitudinally spaced apart legs having openings therein for receiving and slidably supporting the latch bar and a base wall integrally joining said reverse bent edge portion with said spaced apart legs, said base wall having a plurality of slots for receiving fasteners for mounting said support means on the first closure member; and spring means mounted between said support means and said latch bar for biasing said latch bar toward the edge of said second closure member. 